Structural and Superconducting Properties of Thermal Treatment-Synthesised Bulk YBa₂Cu₃O7-δ Superconductor: Effect of Addition of SnO₂ Nanoparticles.

YBa₂Cu₃O7-δ (Y-123) bulk superconductors with the addition of (0.0, 0.2, 0.4, 0.6, 0.8, and 1.0 wt.%) SnO₂ nanoparticles were synthesised via a thermal treatment method. The influence of SnO₂ addition on the superconducting properties by means of critical temperature, Tc, AC susceptibility, phase formation and microstructures, including its elemental composition analysis, were studied. Sharp superconducting transition, ∆Tc, and diamagnetic transition were obtained for all SnO₂-added samples. It was observed that sample x = 0.4 with a Y-123 phase percentage of 95.8% gives the highest Tc, smallest ∆Tc, and the sharpest diamagnetic transition in the normalised susceptibility curves. The microstructure also showed an excess of Sn precipitates on the sample's surface at x = 0.8 and above. As such, the best superconducting properties were observed at x = 0.4 SnO₂ addition inside the Y-123 host sample.